Order ARCHAEOGNATHA

Bristletails

Compiler and date details

Introduction

Archaeognatha, commonly called bristletails, are an extant order of primitively wingless insects. Despite several superficial similarities with the Zygentoma (=Thysanura), it is now widely accepted that the two groups are not closely related and have evolved independently since at least the Carboniferous period. Archaeognatha differ fundamentally from Zygentoma in having monocondylar mandibles (Manton 1964), in the systems of leg articulation (Manton 1972), and muscular and innervation systems (Birket-Smith 1974). Significant differences also occur in moulting control (Watson 1965) but evidence from embryology is not so clear (Jura 1972; Larink 1983).

This homogeneous order is distinguished within the Insecta by its primitive monocondylar mandibles. It retains several other primitive features such as the long series of abdominal styli (almost always on abdominal segments II–IX) and exsertile vesicles (usually on abdominal segments I–VII or II–VII) and, usually, the presence of stylets on the coxae. Archaeognatha also possess a unique escape mechanism: the thoracic and abdominal muscles are rapidly contracted, thrusting the abdomen suddenly against the ground and catapulting the insect into the air and away from danger (Evans 1975).

All species are relatively similar in overall appearance. The body is strongly convex dorsally, and the thorax is strongly arched. The body is covered with pigmented scales. Ocelli and contiguous compound eyes are present. The appendix dorsalis is much longer than the cerci.

One extinct and two living families are known. Sturm & Bach de Roca (1993) suggest that three genera should be removed from the Machilidae to create three new families. Some 460 species in 60 genera are described in the two extant families. Only one of these families, the Meinertellidae, is represented in Australia. Silvestri and Wygodzinsky were the most important early workers on this order and, in recent years, Mendes, Bach de Roca and Sturm have described and reviewed many genera and species, the latter two jointly reviewing the systematics of the order (Sturm & Bach de Roca 1993).

The biology of the Australian species has not been studied. Delany (1954, 1959) examined the biology of three European machilid species and it is probable that the biology of the Australian meinertellid species is similar. The European species were found to be vegetarian, detritus feeders with algae as their major food source.

Acknowledgements

I would like to thank Prof. Helmut Sturm (Hildesheim, Germany) for his valuable comments and help in obtaining literature. Compilation was supported by funds from the Australian Biological Resources Study.

Database Notes

The information on the Australian Faunal Directory site for the Archaeognatha is derived from the Zoological Catalogue of Australia database compiled on the Platypus software program. It incorporates changes made to the work published on 2 September 1998 as (Smith, G.B., 1998)

Limital Area

Distribution data in the Directory is by political and geographic region descriptors and serves as a guide to the distribution of a taxon. For details of a taxon's distribution, the reader should consult the cited references (if any) at genus and species levels.

Australia is defined as including Lord Howe Is., Norfolk Is., Cocos (Keeling) Ils, Christmas Is., Ashmore and Cartier Ils, Macquarie Is., Australian Antarctic Territory, Heard and McDonald Ils, and the waters associated with these land areas of Australian political responsibility. Political areas include the adjacent waters.

Terrestrial geographical terms are based on the drainage systems of continental Australia, while marine terms are self explanatory except as follows: the boundary between the coastal and oceanic zones is the 200 m contour; the Arafura Sea extends from Cape York to 124 DEG E; and the boundary between the Tasman and Coral Seas is considered to be the latitude of Fraser Island, also regarded as the southern terminus of the Great Barrier Reef.

Distribution records, if any, outside of these areas are listed as extralimital. The distribution descriptors for each species are collated to genus level. Users are advised that extralimital distribution for some taxa may not be complete.

Manton, S.M. 1964. Mandibular mechanisms and the evolution of arthropods.Philosophical Transactions of the Royal Society of London B 247: 1-183

Manton, S.M. 1972. The evolution of arthropodan locomotory mechanisms. Part 10. Locomotory habits, morphology and evolution of the hexapod classes.Journal of the Linnean Society of London, Zoology51: 203-400